MI5 knew that Binyam Mohamed, the former Guantanamo detainee, was being
tortured by the CIA, a Court of Appeal judgment has revealed.

Evidence held by the Foreign Office, which had until now been kept secret, shows that the Security Service was aware that Mr Mohamed was deprived of sleep, "shackled" during interrogation and threatened with the idea that he might "disappear".

MI5 has also been accused of feeding questions to Mr Mohamed's interrogators, leading to accusations that it was “complicit” in his torture.

The Foreign Secretary, David Miliband, had repeatedly refused to release details of how much the UK knew about Mr Mohamed's treatment, claiming that doing so would deter the US from sharing intelligence in the future.

But three of the country's highest-ranking judges dismissed his protests because similar material relating to Mr Mohamed had already been published in the US.

They ordered the publication of seven paragraphs of information about Mr Mohamed's treatment in Pakistan which had previously been censored from court papers.

The judgment concluded that Mr Mohamed had been subjected to "cruel, inhuman and degrading treatment by the United States authorities".

It added: “The treatment reported, if had been administered on behalf of the United Kingdom, would clearly have been in breach of the undertakings given by the United Kingdom in 1972 [in the UN convention on torture]."

The human rights organisation Liberty called for a public inquiry into the affair, saying the newly-released material proved the government's "complicity with the most shameful part of the war on terror".

Ethiopian Mr Mohamed, 31, who was granted refugee status when he came to Britain in 1994, was arrested in Pakistan trying to leave the country with a false passport in April 2002.

He was suspected of being an Al-Qaeda operative and fighting with the Taliban in Afghanistan and later subjected to “extraordinary rendition” to Morocco where he was tortured and then to a “dark prison” run by the Americans in Afghanistan before ending up at Guantanamo Bay in Cuba.

He was released from Guantanamo in February last year after the US said he would not face any charges, and on his return to the UK he accused MI5 of being complicit in his torture by feeding questions to his CIA captors.

An MI5 officer who questioned Mr Mohamed in Pakistan is currently the subject of a Scotland Yard investigation into whether he broke international laws on torture.

A ruling by the High Court in 2008 said the role of MI5 went “far beyond that of a bystander or witness to the alleged wrongdoing”.

The judgment released on Wednesday was a revised version of the 2008 ruling, in which the High Court had ordered the release of information to Mr Mohamed’s lawyers relating to his detention.

Seven key paragraphs of the judges’ comments had been redacted after Mr Miliband announced he would appeal against their publication. On Wednesday three Appeal Court judges rejected his appeal, meaning the judgment was published in full for the first time.

It said: “Combined with the sleep deprivation, threats and inducements were made to him. His fears of being removed from United States custody and ‘disappearing’ were played upon.”

This caused Mr Mohamed “significant mental stress and suffering”.

The judgment said that MI5 was told that a new series of interviews were conducted by the United States as part of a new strategy designed by an “expert interviewer.”

Mr Miliband said he accepted the court's decision, but stressed that the ruling respected the principle that countries which share intelligence should only put that material in the public domain with the agreement of the source country.

He added: “We remain determined to uphold our very strong commitment against mistreatment of any kind.”

Shami Chakrabarti, director of Liberty, said: “It has been clear for over a year that the Foreign Office has been more concerned with saving face than exposing torture. These embarrassing paragraphs reveal nothing of use to terrorists but they do show something of the UK government's complicity with the most shameful part of the war on terror.

“The Government has gone to extraordinary lengths to cover up kidnap and torture. A full public inquiry is now inescapable.”

In an unrelated case in the US last November, a judge referred to Mr Mohamed’s two-year torture ordeal, saying: “During that time he was physically and psychologically tortured. His genitals were mutilated. He was deprived of sleep and food. He was summarily transported from one foreign prison to another. Captors held him in stress positions for days at a time. He was forced to listen to piercingly loud music and the screams of other prisoners while locked in a pitch black cell.

All the while he was forced to inculpate himself and others in various plots to imperil Americans. The Government does not dispute this evidence.”